Papers by Sophie G Pitois
Jellyfish are increasingly recognised as important components of the marine ecosystem, yet their ... more Jellyfish are increasingly recognised as important components of the marine ecosystem, yet their specific role is poorly defined compared to that of other zooplankton groups. This paper presents the first global ocean biogeochemical model that includes an explicit representation of jellyfish, and uses the model to gain insight into the influence of jellyfish on the plankton community. The PlankTOM11 model groups organisms into Plankton Functional Types (PFT). The jellyfish PFT is parameterised here based on our synthesis of observations on jellyfish growth, grazing, respiration and mortality rates as functions of temperature and on jellyfish biomass. The distribution of jellyfish is unique compared to that of other PFTs in the model. The jellyfish global biomass of 0.13 PgC is within the observational range, and comparable to the biomass of other zooplankton and phytoplankton PFTs. The introduction of jellyfish in the model has a large direct influence on the crustacean macrozooplankton PFT, and influences indirectly the rest of the plankton ecosystem through trophic cascades. The zooplankton community in PlankTOM11 is highly sensitive to the jellyfish mortality rate, with jellyfish increasingly dominating the zooplankton community as its mortality diminishes. Overall the results suggest that jellyfish play an important and unique role in regulating marine plankton ecosystems, which has been neglected so far.
Frontiers in Marine Science
Three plankton collection methods were used to gather plankton samples in the Celtic Sea in Octob... more Three plankton collection methods were used to gather plankton samples in the Celtic Sea in October 2016. The Plankton Image Analysis (PIA) system is a high-speed color line scan-based imaging instrument, which continuously pumps water, takes images of the passing particles, and identifies the zooplankton organisms present. We compared and evaluated the performance of the PIA against the Continuous Automatic Litter and Plankton Sampler (CALPS) and the traditional ring net vertical haul. The PIA underestimated species abundance compared to the CALPS and ring net and gave an image of the zooplankton community structure that was different from the other two devices. There was, however, good agreement in the spatial distribution of abundances across the three systems. Our study suggests that the image capture and analysis step rather than the sampling method was responsible for the discrepancies noted between the PIA and the other two datasets. The two most important issues appeared to be differences in sub-sampling between the PIA system and the other two devices, and blurring of specimen features due to limited PIA optical depth of field. A particular advantage of the CALPS over more traditional vertical sampling methods is that it can be integrated within existing multidisciplinary surveys at little extra cost without requiring additional survey time. Additionally, PIA performs automatic image acquisition and it does remove the need to collect physical preserved samples for subsequent analysis in the laboratory. With the help of an expert taxonomist the system in its current form can also integrate the sampling and analysis steps, thus increasing the speed, and reducing the costs for zooplankton sampling in near real-time. Although the system shows some limitation we believe that a revised PIA system will have the potential to become an important element of an integrated zooplankton monitoring program.
Frontiers in Marine Science
Marine environmental monitoring is undertaken to provide evidence that environmental management t... more Marine environmental monitoring is undertaken to provide evidence that environmental management targets are being met. Moreover, monitoring also provides context to marine science and over the last century has allowed development of a critical scientific understanding of the marine environment and the impacts that humans are having on it. The seas around the UK are currently monitored by targeted, impact-driven, programmes (e.g., fishery or pollution based monitoring) often using traditional techniques, many of which have not changed significantly since the early 1900s. The advent of a new wave of automated technology, in combination with changing political and economic circumstances, means that there is currently a strong drive to move toward a more refined, efficient, and effective way of monitoring. We describe the policy and scientific rationale for monitoring our seas, alongside a comprehensive description of the types of equipment and methodology currently used and the technologies that are likely to be used in the future. We contextualize the way new technologies and methodologies may impact monitoring and discuss how whole ecosystems models can give an integrated, comprehensive approach to impact assessment. Furthermore, we discuss how an understanding of the value of each data point is crucial to assess the true costs and benefits to society of a marine monitoring programme.
Frontiers in Marine Science, 2016
Marine environmental monitoring has tended to focus on site-specific methods of investigation. Th... more Marine environmental monitoring has tended to focus on site-specific methods of investigation. These traditional methods have low spatial and temporal resolution and are relatively labor intensive per unit area/time that they cover. To implement the Marine Strategy Framework Directive (MSFD), European Member States are required to improve marine monitoring and design monitoring networks. This can be achieved by developing and testing innovative and cost-effective monitoring systems, as well as indicators of environmental status. Here, we present several recently developed methodologies and technologies to improve marine biodiversity indicators and monitoring methods. The innovative tools are discussed concerning the technologies presently utilized as well as the advantages and disadvantages of their use in routine monitoring. In particular, the present analysis focuses on: (i) molecular approaches, including microarray, Real Time quantitative PCR (qPCR), and metagenetic (metabarcoding) tools; (ii) optical (remote) sensing and acoustic methods; and (iii) in situ monitoring instruments. We also discuss Danovaro et al. Innovative Approaches in Marine Monitoring their applications in marine monitoring within the MSFD through the analysis of case studies in order to evaluate their potential utilization in future routine marine monitoring. We show that these recently-developed technologies can present clear advantages in accuracy, efficiency and cost.
Journal of Plankton Research, 2016
We compared and evaluated the performance of a Continuous Automatic Litter and Plankton Sampler (... more We compared and evaluated the performance of a Continuous Automatic Litter and Plankton Sampler (CALPS) against the traditional ring net vertical haul. CALPS is a custom-made semi-automatic sampler, which collects water using a pump system at a single depth along a predetermined transect as the ship sails. CALPS underestimated species abundance compared to the ring net by a factor 1.61, but both datasets illustrated a similar species composition, community size structure and good agreement in the spatial distribution of abundance. Our analysis suggests that avoidance of the CALPS is likely to be the main factor responsible for the observed difference in sampling efficiency, but other factors, such as depth, area sampled and zooplankton patchiness, are also likely to play their part. We conclude that whilst the CALPS is not suitable for investigations that require accurate measures of abundance, it is an ideal tool to identify and quantify changes in plankton communities and diversity. A particular advantage over more traditional vertical sampling methods is that it can be integrated within existing multidisciplinary surveys at little extra cost, thus making the CALPS particularly valuable as part of integrated monitoring programmes to underpin policy areas such as the EU Marine Strategy Framework Directive.
GigaScience, 2015
Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinf... more Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world's oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits.
Journal of environmental health, 2001
Blooms of cyanobacteria (toxic blue-green algae) can produce health and environmental hazards in ... more Blooms of cyanobacteria (toxic blue-green algae) can produce health and environmental hazards in water, including water used for drinking or recreational purposes. How, why, and when these blooms are produced, as well as how to deal with them, are questions whose answers are vital to the safeguarding of public health in regions where the algae occur. The blooms are linked to eutrophication of water, and this paper discusses the eutrophication problems, their nature, and their relevance to the production of cyanobacteria. Nutrient limitations on algal productivity are considered, as is the involvement of the atmosphere, the storage of nutrients in soils, and the influence of anthropogenic activity.
Continental Shelf Research, 2015
The value of the Continuous Plankton Recorder (CPR) fish larvae dataset, with its extensive spati... more The value of the Continuous Plankton Recorder (CPR) fish larvae dataset, with its extensive spatiotemporal coverage, has been recently demonstrated with studies on long-term changes over decadal scales in the abundance and distribution of fish larvae in relation to physical and biological factors in the North Sea. We used a similar approach in the west and southwest area of the UK shelf and applied a principal component analysis (PCA) using 7 biotic and abiotic parameters, combined with Hierarchical Cluster Analysis (HCA), to investigate the impact of environmental changes in the west and southwest area of the UK shelf on mackerel larvae during the period 1960-2004. The analysis revealed 3 main periods of time () reflecting 3 different ecosystem states. The results suggest a transition from an ecosystem characterized by low temperature, high salinity, high abundances of zooplankton and the larger phytoplankton groups, to a system characterized by higher temperature, lower salinities, lower abundances of zooplankton and larger phytoplankton and higher abundances of the small phytoplankton species. Analysis revealed a very weak positive correlation between the Second principal component and mackerel larvae yearly abundance, attributed to the North Atlantic Oscillation (NAO). The results presented here are in broad accord with recent investigations that link climatic variability and dynamics of mackerel reproduction. However, the growing body of literature that documents statistical correlations between environment and mackerel needs to be supplemented by local process studies, to gain more insight and to be able to predict mackerel response to climate change scenarios. Utilising the strength of the CPR dataset, namely its unique temporal coverage, in an analysis where other data (such as egg surveys) are drawn in to compensate for the spatial issues could prove to be the way forward. Crown
ABSTRACT The ICES/CIESM Joint Workshop on Mnemiopsis Science (JWMS) chaired by Sophie Pitois (UK)... more ABSTRACT The ICES/CIESM Joint Workshop on Mnemiopsis Science (JWMS) chaired by Sophie Pitois (UK) and Tamara Shiganova (Russia), met in A Coruña, Spain from 18 to 20 September 2014. Scientists affiliated with the International Council for the Exploration of the Sea (ICES) and the Mediterranean Science Commission (CIESM) participated in the Joint Workshop to discuss the latest advances regarding the biogeography, ecology, impact and economic aspects of the invasive ctenophore Mnemiopsis leidyi and its Beroe predators (both native and invasive). The JWMS was attended by 20 scientists from 14 countries. The main objective of the workshop was to provide a forum for scientists to present and discuss the results of ongoing relevant research projects in the North Atlantic and Mediterranean. The 13 presentations stimulated wide ranging discussions relevant to Mnemiopsis science. Highlights • The latest knowledge regarding the biogeography and ecology of Mnemiopsis leidyi and of its Beroe predators were reviewed, as well as the spatialand temporal occurrences across the ICES-CIESM sea basins. It was recognized that Beroe spp. are not the only predators of M. leidyi and that the various interactions of M. leidyi with the different components of the ecosystem, as well as mechanisms involved, are too complex to be comprehensively understood. • Mnemiopsis leidyi is most likely exhibiting source-sink population dynamics within its European range. • European seas are warming at present, and temperature is likely to affect the timing and distribution of both M. leidyi and Beroe spp. in those areas. However, the link with temperature was questioned, and the hypothesis was put forward, that food web pertubations from overfishing combined with eutrophication in coastal areas and major influx of invasive aliens, have permitted the establishment of Mnemiopsis propagules in some areas. • M. leidyi has a wide environmental tolerance and phenotypic variability. Environmental conditions influence the development of M. leidyi, however it can establish in highly contrasting ecosystems. Its morphological features, growth rate, metabolism, size of maturity, fecundity differ according to environmental conditions particularly considering salinity, temperature, productivity and prey concentration. • Modelling tools, based on experimental physiological knowledge, help to predict/understand the aforementioned processes and interactions. Several approaches were presented and discussed. • At the same time it was acknowledged that there is not enough information on M. leidyi occurrence, seasonal and interannual variability in some areas, particularly in northern Europe and specific areas of the Mediterranean Sea. Improved monitoring and more comprehensive coverage of investigated areas are therefore deemed necessary, in particular field investigations of overwintering areas are needed. • A key parameter to understand population dynamics is the winter biology of M. leidyi. Therefore more research effort should be devoted (i) to understand the low temperature/low food environmental interactions with M. leidyi and its survival under these conditions; (ii) to identify sites of overwintering populations. • Citizen science may provide a valuable tool to improve our knowledge on poorly monitored areas, and should be encouraged.
Fisheries Oceanography, 2014
ABSTRACT We applied a physiological individual-based model for the foraging and growth of cod (Ga... more ABSTRACT We applied a physiological individual-based model for the foraging and growth of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) larvae, using observed temperature and prey fields data from the Irish Sea, collected during the 2006 spawning season. We used the model to estimate larval growth and survival and explore the different productivities of the cod and haddock stocks encountered in the Irish Sea. The larvae of both species showed similar responses to changes in environmental conditions (temperature, wind, prey availability, daylight hours) and better survival was predicted in the western Irish Sea, covering the spawning ground for haddock and about half of that for cod. Larval growth was predicted to be mostly prey-limited, but exploration of stock recruitment data suggests that other factors are important to ensure successful recruitment. We suggest that the presence of a cyclonic gyre in the western Irish Sea, influencing the retention and/or dispersal of larvae from their spawning grounds, and the increasing abundance of clupeids adding predatory pressure on the eggs and larvae; both may play a key role. These two processes deserve more attention if we want to understand the mechanisms behind the recruitment of cod and haddock in the Irish Sea. For the ecosystem-based management approach, there is a need to achieve a greater understanding of the interactions between species on the scale a fish stock is managed, and to work toward integrated fisheries management in particular when considering the effects of advection from spawning grounds and prey–predator reversal on the recovery of depleted stocks.
Marine Ecology Progress Series, 2012
Journal of Plankton Research, 2008
Journal of Marine Systems, 2009
A changing Earth System requires knowledge on a global scale. The only way of obtaining detailed ... more A changing Earth System requires knowledge on a global scale. The only way of obtaining detailed information at these scales is by using satellite remote sensing and/or modeling. In the marine environment, information on primary production (PP) is derivable from satellite data, whereas datasets of higher trophic levels are sparse. The challenge is to combine these two sources. A model relating the flow of energy from PP to zooplankton biomass, was used to address this problem. The model was parameterised with PP from the SeaWiFS satellite ocean colour record and a subset of a global dataset of zooplankton biomass. The model was then validated with the remaining zooplankton data. The model was used to: produce a map of annual global, zooplankton biomass, quantify the flow of carbon from PP to zooplankton and investigate the spatial variability of this flow. One of the more notable findings is that more energy is transferred to zooplankton when PP is low.
International Journal of Environmental Health Research, 1997
ABSTRACT Nutrient levels (phosphorus and nitrogen) were measured in a small reservoir in Scotland... more ABSTRACT Nutrient levels (phosphorus and nitrogen) were measured in a small reservoir in Scotland between March 1994 and October 1995. Algae species were identified. Dense blooms of Gloeotrichia echinulata have regularly occurred in late summer in the reservoir for many years, but it did not reach bloom proportions during the 1995 summer and seemed to have been replaced by Aphanizomenon. The bloom of the cyanobacterium Gloeotrichia echinulata that occurred in August 1994 was studied in relation to phosphorus levels present at the time in the water. Results show that the bloom developed after a slight increase in dissolved inorganic phosphorus; while the bloom was developing, particulate inorganic forms of phosphorus increased and were then replaced by particulate organic forms when the bloom reached its maximum density. All phosphorus fractions started to decrease shortly before the bloom collapsed. Our study showed that there did not seem to be any change in the distribution of phosphorus between its different fractions, at least during the first 24 h after collection when the sample was kept in a refrigerator in the dark. We therefore conclude that Gloeotrichia echinulata was probably responsible for transferring phosphorus from the sediments up to the water column in Antermony.
International Journal of Environmental Health Research, 2000
Eutrophication of waters can lead to the development of blooms of cyanobacteria (blue-green algae... more Eutrophication of waters can lead to the development of blooms of cyanobacteria (blue-green algae) and consequent health and environmental problems. The presence of these organisms in recreational and drinking waters is generally undesirable or even hazardous, although nitrogen fixing blue-green algae can be beneficially used as biofertilisers for plantation crops. This paper reviews the characteristics of cyanobacteria and particularly their
ICES Journal of Marine Science, 2013
Lynam, C. P., Halliday, N. C., Höffle, H., Wright, P. J., van Damme, C. J. G., Edwards, M., and P... more Lynam, C. P., Halliday, N. C., Höffle, H., Wright, P. J., van Damme, C. J. G., Edwards, M., and Pitois, S. 2013. Spatial patterns and trends in abundance of larval sandeels in the North Sea: 1950–2005 – ICES Journal of Marine Science, 70: 540–553. Early recruitment indices based on larval fish data from the Continuous Plankton Recorder (CPR) have the potential to inform stock assessments of Ammodytes marinus in the North Sea. We evaluate whether the CPR data are reliable for sandeel larvae. Spatially, CPR larval data were comparable with catches by dedicated larval samplers (Gulf and bongo nets) during ICES coordinated surveys in 2004 and 2009. ICES data are also used to explore environmental influences on sandeel distributions. Temporally, CPR data correlate with larval data from plankton surveys off Stonehaven (1999–2005), with sandeel 0-group trawl data at the east Fair Isle ground (since 1984), and with recruitment data (since 1983) for the Dogger Banks stock assessment area. Th...
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Papers by Sophie G Pitois